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November 4, 2007

Wasted energy from nuclear power could spark Hydrogen Renaissance

The key to establishing a hydrogen-powered rail corridor in Toronto is Nuclear energy, says Greg Naterer, a professor of mechanical engineering at the University of Ontario Institute of Technology.

The big issue with hydrogen is that 96 per cent of what's produced in the world comes from fossil fuels, particularly natural gas, through a process called steam reforming. This results in greenhouse gases and other emissions.

The rest largely comes from a more expensive process called electrolysis, which is the use of electricity to separate water molecules into oxygen and hydrogen.

Electrolysis has the potential to produce emission-free hydrogen, but only if the source electricity is itself emission-free – that is, it must come from wind, solar or hydroelectric generation. Nuclear power, if you ignore the radioactive waste, also fits the bill, and this has turned the nuclear industry into a big hydrogen-economy supporter as a way of boosting its own self-proclaimed renaissance.

"A hydrogen economy doesn't make sense if we're using fossil fuels to generate the hydrogen, so we need a method that doesn't use fossil fuels," says Naterer. "And right now hydrogen from electrolysis is too costly because it has to compete against other fuels."

As research chair in advanced energy systems at UOIT, Naterer is leading a 24-member team that's exploring a method of producing lower-cost hydrogen from the waste heat of nuclear plants. Atomic Energy of Canada Ltd., the Argonne National Laboratory near Chicago and universities across Ontario are also participating in the research effort.

Some have argued that surplus electricity from the overnight operation of nuclear reactors could be used to produce hydrogen, but UOIT and its research partners have their eye on a more economical approach. Instead of using nuclear power directly for electrolysis, they plan to use the waste heat from a nearby nuclear plant to extract hydrogen from steam.

What happens is the steam reacts with copper and chlorine compounds through a five-step process that splits water. It's a closed cycle, meaning the copper and chlorine is recycled and no waste is produced.

"All you have going in is water and all that comes out is hydrogen and oxygen," says Naterer, adding that the process is more than 33 per cent more efficient than electrolysis and makes hydrogen production cost-competitive with the fossil-fuel approach, once carbon taxes and the future cost of carbon capture and storage are factored in.

The process doesn't rely exclusively on nuclear – waste heat from any industrial operation will do, assuming there's enough. But given the proximity of Ontario nuclear plants to the GO train corridor, and the massive amounts of waste heat that could be tapped, researchers see huge potential in McGuinty's proposal.

He says an initial pilot plant would produce enough of the gas to fuel a couple of trains travelling between Oshawa and Toronto. Once the technique is proven, it could be scaled up 1,000 times – enough hydrogen for GO's entire train fleet and hundreds of thousands of vehicles.